HELP! (Foundation cracks)


  #1  
Old 06-01-09, 05:16 PM
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HELP! (Foundation cracks)

Hello;

I am about to purchase a house, and need some expert advise on "cracks" in a foundation. The house in question is located in Halifax Nova Scotia, is 8 years old,

The house is a bungalow, with a 10 inch thick foundation wall situated on a larger footing. The house itself is built on bedrock. When walking around the exteriour, I have counted 5 cracks...some verticcal and some diagonal.

The diagonal cracking seems to occur when the foundation wall has a 'step down'.

Most of these cracks are 'hairline' , but one in particular is a bit bothersome. It is the largest and...when a straight edge is placed on the wall face, (credit card) there is about a 1/8 inch "step" as if one side of the wall has been slightly "pushed in". creating a bit of a 'ridge' on either side of the crack.

There is also many spider cracks on the garage floor and one larger crack from the that travels from the beginning of the entrance toward the middle of the gatage. None of these cracks appear to be "stepped".

I have pictures, but not sure how to post them here.

I thank everyone in advance for any help they can deliver.

J
 
  #2  
Old 06-02-09, 02:57 AM
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In general, concrete cracks are nothing to worry about. In any mass of concrete, there will be cracks. This is especially true in a foundation, where no joints are used to control shrinkage cracking. The concrete has to give somewhere, so it makes its own joints by cracking. If the concrete on either side of the crack is noticeably higher or lower than the other side, you have some vertical movement which could possibly indicate a problem. If it's only 1/8 inch like you say, that's not much.
In the garage, how many joints were cut into the slab? If they are not deep enough (minimum 1" deep for a 4" thick slab), or spaced closely enough, or if there are any un-jointed re-entrant corners, then the concrete will have cracks. If they are only hairline cracks, don't worry about them.
Re-entrant corners are formed corners where the concrete was poured around something like a wall, or any other corner that points into the slab. For instance, your foundation step downs form a re-entrant corner pointing into the foundation. Cracks typically occur at a 45 degree angle to the point of the re-entrant corner. Slabs should be jointed at re-entrant corners, but of course walls can't be.
This is all general info, your situation could be somehow different.
 
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Old 06-02-09, 10:14 AM
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Thanks for the info Peco. I think I will hire someone to take a look see.
 
 

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